JP2002033673A - Receiver for mobile wireless communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver with the reduced current consumption for a mobile wireless communication unit adopting a configuration such that a wireless frequency signal is converted into a 1st intermediate frequency signal, the 1st intermediate frequency signal is amplified and then the amplified signal is converted into a 2nd intermediate frequency signal. SOLUTION: The receiver is provided with a received signal discrimination circuit 18 that discriminates presence of a received signal based on an output signal from an intermediate frequency amplifier circuit 8 and with an operation control circuit 19 that stops at least the operation of a part of a 2nd frequency conversion circuit 24 when no received signal exists on the basis of the discrimination result by the received signal discrimination circuit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving device provided in a mobile radio communication device (mobile station of a mobile radio communication system), and more particularly, to a Bluetooth device mounted on a mobile radio communication device such as a portable telephone. The present invention relates to a receiving device suitable as an interface RF (radio frequency) receiver IC (integrated circuit).

[0002]

2. Description of the Related Art A receiving device in a mobile radio communication system is usually driven by a battery. Therefore, low power consumption is desired to extend the life of the battery. In particular, R of a mobile station (mobile radio communication device) in a mobile radio communication system
A receiving circuit such as an F receiver IC usually uses a battery as a power supply, and thus needs to minimize current consumption. Therefore, techniques for reducing the power consumption of the receiving device have been conventionally proposed.

[0003] As this kind of prior art, Japanese Patent Laid-Open Publication No.
No. 0464 discloses a received signal electric field strength signal (hereinafter referred to as R
A control method of a receiving apparatus that controls the local level of a local signal based on the value of an SSI signal has been proposed. This control method utilizes the characteristic that the reception sensitivity decreases as the local level decreases.

FIG. 5 is a block diagram of a receiving apparatus using this control method. In FIG. 5, reference numeral 101 denotes an input terminal to which a received signal is input, 102 denotes a reception band-pass filter connected to the input terminal 101, and 103 denotes an amplification unit that amplifies a signal passed through the reception band-pass filter 2. It is a top amplifier as a circuit.

A mixing circuit 104 mixes a signal output from the top amplifier 103 with a first local signal.
An amplifier 105 amplifies the first local signal supplied to the mixing circuit 104, a first local oscillator 106 for outputting the first local signal, and a first intermediate frequency band pass 107 connected to the mixing circuit 104. Filter.

Reference numeral 108 denotes an amplifier for amplifying a signal that has passed through the first intermediate frequency band-pass filter 107.
Is a mixing circuit for mixing the output of the amplifier 108 with a second local signal, and 110 is a mixing circuit 109
Amplifier for amplifying the second local signal to the
Is a second local oscillator for outputting a second local signal, 112
Is a second intermediate frequency bandpass filter connected to the mixing circuit 109.

Reference numeral 113 denotes a demodulator with a detection circuit as a detection / demodulation means for demodulating the signal passed through the second intermediate frequency band-pass filter 112 and detecting the input electric field intensity, and 114 denotes the demodulated signal. Is an output terminal from which is output, and 115 is an RSSI terminal (detection output terminal) from which a detection signal is output.

Reference numeral 116 denotes a switching control circuit for generating a current switching signal based on the DC voltage value of the detection signal output from the RSSI terminal 115. Reference numeral 117 denotes a current switching signal, and 117 A current switching circuit that inputs the signal to the amplifier 105 that amplifies the signal and controls the local level of the first local signal.

[0009] That is, the above-mentioned conventional receiving apparatus is capable of detecting and detecting.
An amplifier that amplifies the first local signal according to a current switching signal generated based on a detection signal from a demodulation unit;
By controlling the first local signal level by switching the current supplied to the receiver 05, the receiving sensitivity is reduced in a place where the received electric field strength is sufficiently large, thereby realizing a receiving apparatus that prevents wasteful consumption of the battery.

[0010]

As described above, the conventional receiving apparatus controls the amount of current supplied to the amplifier 105 which amplifies the first local signal based on the DC voltage value of the RSSI signal. This reduces current consumption.

However, in the above-mentioned conventional receiving apparatus,
All circuits are always operating regardless of the presence or absence of a reception signal, and circuits that do not always need to operate when there is no reception signal, for example, the amplifier 110 and the second local oscillator 111
However, there is a problem that current consumption is wasted due to such factors.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to reduce a wasteful current consumption in a standby mode, thereby reducing a current consumption of a mobile radio communication device. To provide a receiving device.

[0013]

Means for Solving the Problems The present inventor has made intensive studies on a receiving device of a mobile radio communication apparatus in order to solve the above-mentioned problems. Output, and the presence or absence of a received signal is determined based on the value of the RSSI signal, and by controlling the activation of the second frequency conversion unit that converts the first intermediate frequency signal into the second intermediate frequency signal based on the determination result. ,
The inventors have found that the above-mentioned problems can be solved, and have completed the present invention.

That is, in order to solve the above-mentioned problems, a receiving apparatus for a mobile radio communication device according to the present invention comprises: a first frequency converter for converting a radio frequency signal into a first intermediate frequency signal; Comprising: an intermediate frequency amplifier for amplifying the intermediate frequency signal of the first type; and a second frequency conversion unit for converting the first intermediate frequency signal to a second intermediate frequency signal having a frequency different from that of the first intermediate frequency signal. In a receiving device of a wireless communication device, a receiving signal determining unit that determines the presence or absence of a receiving signal based on an output signal of an intermediate frequency amplifier; Operation control means for stopping at least a part of the operation of the conversion unit.

According to the above configuration, when there is no received signal, at least a part of the operation of the second frequency conversion unit is stopped. Therefore, it is possible to reduce unnecessary current consumption during standby. As a result, the power consumption of the receiving device,
In addition, the current consumption of the entire mobile radio communication device can be reduced.

Further, according to the above configuration, the presence or absence of a received signal is determined based on the level of the output signal of the intermediate frequency amplifier. Thus, even when the entire operation of the second frequency conversion unit is stopped, all of the second frequency conversion units can be activated when the reception signal is input. In addition, after converting the received radio frequency signal to an intermediate frequency and amplifying it, the presence or absence of a received signal is determined based on the level thereof. The influence can be suppressed. As a result, the presence or absence of a received signal can be accurately determined.

On the other hand, in a system in which control is performed based on the output of the demodulator 113 with a detection circuit as in the above-described conventional receiver, if the operation of the mixing circuit 109 is stopped once, an RSSI signal is obtained. It is gone, and control becomes impossible. Therefore, in a system in which control is performed based on the output of the demodulator 113 with a detection circuit as in the conventional receiving apparatus, the mixing circuit 10 is used only during standby.
It is impossible to stop the operation of No. 9.

[0018] Further, in order to solve the above-mentioned problems, a receiving device for a mobile radio communication device according to the present invention converts a radio frequency signal into:
A first mixer for mixing with the first local oscillation frequency signal to convert it into a first intermediate frequency signal, a first local oscillator for outputting the first local oscillation frequency signal, and a first local oscillation frequency signal For amplifying the signal and supplying the amplified signal to the first mixer
An amplifier, an intermediate frequency amplifier for amplifying the first intermediate frequency signal, and an amplifier for mixing the amplified first intermediate frequency signal with a second local oscillation frequency signal to convert the mixed signal into a second intermediate frequency signal. A mobile radio comprising a second mixer, a second local oscillator for outputting a second local oscillation frequency signal, and a second amplifier for amplifying and supplying the second local oscillation frequency signal to the second mixer. In a receiving device of a communication device, a receiving signal determining means for determining the presence or absence of a receiving signal based on the level of an output signal of the intermediate frequency amplifier; At least one of a mixer, a second local oscillator, and a second amplifier
Operation control means for stopping one operation.

According to the above configuration, when there is no received signal, the operation of at least one of the second mixer, the second local oscillator, and the second amplifier is stopped. Therefore, it is possible to reduce unnecessary current consumption during standby. As a result, it is possible to reduce the power consumption of the receiving device and the current consumption of the entire mobile radio communication device.

Further, according to the above configuration, the presence or absence of a received signal is determined based on the level of the output signal of the intermediate frequency amplifier. Thus, even when the operation of the second mixer is stopped, the second mixer (and the second local oscillator and the second amplifier) are activated when the received signal is input after the operation of the second mixer is stopped. Can be activated. In addition, after converting the received radio frequency signal to an intermediate frequency and amplifying it, the presence or absence of a received signal is determined based on the level thereof. The influence can be suppressed. As a result, the presence or absence of a received signal can be accurately determined.

Preferably, the operation control means stops at least the operation of the second local oscillator when there is no received signal, based on the result of the judgment by the received signal judgment means.

In the conventional receiving apparatus, there is also a problem that the leaked local signal radiated from the second local oscillator causes interference with other circuit parts. Therefore, depending on the problem that the output level of the RSSI signal fluctuates due to the interference of the leaked signal from the second local oscillator to the receiving unit and the layout of the circuit (IC), the wiring is extended for a long time. A problem arises in that a leak signal may get on the wiring as noise and adversely affect circuit operation.

On the other hand, when the operation of at least the second local oscillator is stopped when there is no received signal as in the above configuration, the second local oscillator that has leaked from the second local oscillator during standby mode can be obtained.
It is possible to prevent the local oscillation frequency signal from interfering with other circuit parts. Therefore, it is possible to prevent fluctuations in the output level of the RSSI signal and adverse effects on the operation of other circuit parts.

Further, in the above-mentioned configuration in which at least the operation of the second local oscillator is stopped, the operations of the second mixer, the second local oscillator, and the second amplifier are controlled by an externally input bias current. The operation control means cuts off (off) the input of the bias current to the second mixer, the second local oscillator, and the second amplifier when there is no reception signal, based on the result of the determination by the reception signal determination means. By doing so, it is preferable to stop the operations of the second mixer, the second local oscillator, and the second amplifier.

According to the above configuration, when there is no received signal, all operations of the second mixer, the second local oscillator, and the second amplifier are stopped, so that the second mixer, the second local oscillator, and the second local oscillator are stopped. All power consumption of the two amplifiers can be reduced. Therefore, power consumption can be further reduced.

Further, in the above configuration, since the operation of the second mixer, the second local oscillator, and the second amplifier is stopped by cutting off the input of the bias current, the power consumption can be reduced more reliably.

In the receiving apparatus of the present invention, the received signal determining means compares the level of the output signal of the intermediate frequency amplifier with a threshold value, and the level of the output signal of the intermediate frequency amplifier is higher than the threshold value. In this case, while it is determined that there is a received signal, it is preferable to determine that there is no received signal when the level of the output signal of the intermediate frequency amplifier is equal to or lower than the threshold value.

According to the configuration, the received signal determination means determines that there is no received signal when the level of the output signal of the intermediate frequency amplifier is equal to or less than the threshold value. If the threshold value is set higher than the maximum noise level, it can be determined that there is no received signal even when the output signal of the intermediate frequency amplifier contains only noise and no received signal. Therefore, even if noise is included in the output signal of the intermediate frequency amplifier, when there is no received signal, at least one of the second frequency converter, the second mixer, the second local oscillator, and the second amplifier is used. By stopping one operation, power consumption can be reduced. Therefore, power consumption can be further reduced.

It is preferable that the threshold value required for determining the presence or absence of a received signal can be changed by control by a user, software, or the like. Preferably, it can be changed by control. That is, the receiving device having the above configuration includes a threshold changing unit that changes the threshold, and a control unit that controls the threshold changing unit such that the threshold changes according to the level of the received signal. It is particularly preferable to further include

Thus, it is possible to determine the presence or absence of a reception signal according to the reception situation. Therefore, the presence or absence of a received signal can be determined more accurately.

It is preferable that the receiving apparatus of the mobile radio communication apparatus according to the present invention further includes a selecting means for selecting a signal of a specific channel from the first intermediate frequency signal, for example, a band pass filter. . This makes it possible to more accurately determine the presence or absence of a received signal.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the receiving apparatus of the mobile radio communication apparatus according to the present embodiment has an input terminal 1, a reception band band-pass filter 2, a high-frequency amplifier circuit 3, a first frequency conversion circuit (a first frequency conversion unit). ) 23, an intermediate frequency band-pass filter 7, an intermediate frequency amplifying circuit 8, a second frequency converting circuit (second
A frequency converter 23, a demodulator 13 with a detection circuit, and an output terminal 14.

The input terminal 1 receives a radio frequency (RF) signal received from an antenna (not shown) provided outside the receiving device. The reception band bandpass filter 2 is connected to the input terminal 1 and receives the RF signal.
It has a function of removing interfering waves in a band other than the reception band from a signal and a function of protecting a subsequent circuit from lightning and the like. The high frequency amplifier circuit 3 amplifies the RF signal that has passed through the reception band bandpass filter 2.

The first frequency conversion circuit 23 includes a first mixer 4, a first local signal amplifier (first amplifier) 5, and a first local oscillator 6. First mixer 4
Converts the RF signal into a first IF signal by mixing the RF signal output from the high-frequency amplifier circuit 3 with a first local signal (a first local oscillation frequency signal). The first local oscillator 6 outputs a first local signal supplied to the first mixer 4. The first local signal amplifier 5 is configured to output the first local signal
The local signal is amplified and supplied to the first mixer 4.

The intermediate frequency band-pass filter 7 is connected to the first mixer 4 and passes only the first IF signal having a desired channel frequency among the first IF signals output from the first mixer 4. It is. The intermediate frequency amplifier 8 amplifies the first IF signal that has passed through the intermediate frequency band pass filter 7.

The second frequency conversion circuit 24 includes a second mixer 9, a second local signal amplifier (second amplifier) 10, and a second local oscillator 11. The second mixer 9 mixes the first IF signal output from the intermediate frequency amplifier circuit 8 with the second local signal (second local oscillation frequency signal) to convert the RF signal into a second IF signal having a frequency different from that of the first IF signal. This is converted into a signal. The second local oscillator 11 outputs a second local signal to be supplied to the second mixer 9. Second local signal amplifier 1
0 is for amplifying the first local signal output from the second local oscillator 11 and supplying it to the second mixer 9.

The demodulator 13 with a detection circuit is provided in the second mixer 9
Detects the second IF signal output from the first IF signal and transmits the second IF signal to an original signal before transmission (for example, an audio signal)
Detection and demodulation means. The output terminal 14 outputs the signal demodulated by the demodulator 13 with a detection circuit to an output device provided outside the receiving device, for example, an audio output device.

The above components are almost the same as those of the receiving apparatus shown in FIG.

The receiving apparatus of this embodiment includes an RSSI terminal 15, a received signal determination circuit (received signal determination means) 18, and an operation control circuit (operation control means) 19, in addition to the above components. The RSSI terminal 15 is provided in the intermediate frequency amplifying circuit 8 and converts the first IF signal amplified by the intermediate frequency amplifying circuit 8 into an RS signal representing a received electric field level of a received signal.
This is for outputting to the received signal determination circuit 18 as an SI signal.

The received signal determination circuit 18 is connected to the RSSI terminal 1
5 is for determining the presence or absence of a received signal based on the voltage level (DC voltage value) of the RSSI signal output from 5.

The operation control circuit 19 includes the reception signal determination circuit 1
Based on the result of the determination in step 8, the second mixer 9, the second local signal amplifier 10, and the second local oscillator 11 are activated. Specifically, the operation control circuit 19
When the reception signal determination circuit 18 determines that there is a reception signal, the second mixer 9, the second local signal amplifier 10,
When all the second local oscillators 11 are activated and the reception signal determination circuit 18 determines that there is a reception signal,
The operation of at least one of the second mixer 9, the second local signal amplifier 10, and the second local oscillator 11 is stopped.

Next, the operation of the receiving apparatus according to the present embodiment will be described.

First, when a received RF signal is inputted from an input terminal, the RF signal is subjected to a reception band band-pass filter 2 to remove unnecessary frequency components other than the reception band, and then to the high frequency amplifier circuit 3. Amplified. Next, the amplified RF signal is sent to the first mixer 4, where the amplified RF signal is frequency-converted to an intermediate frequency by being mixed with the first local signal output from the first local oscillator 6. It becomes the first IF signal.

The first IF signal obtained by the frequency conversion passes through the intermediate frequency band-pass filter 7,
After the extra frequency components other than the frequency of the desired channel are removed, the signal is sent to the intermediate frequency amplifier circuit 8. The first IF signal sent to the intermediate frequency amplifying circuit 8 is amplified by the intermediate frequency amplifying circuit 8 and then sent to the second mixer 9.
The received signal is output from the RSSI terminal 15 to the received signal determination circuit 18 as an RSSI signal indicating the received electric field strength.

The first IF signal sent to the second mixer 9 is
The second mixer 9 mixes the second local signal output from the second local oscillator 11 with the first local
The frequency is converted to an intermediate frequency different from the frequency of the F signal to be a second IF signal. The second IF signal is detected by the demodulator 13 with a detection circuit and demodulated into an original signal (for example, an audio signal) before transmission.
4 is output.

On the other hand, the reception signal determination circuit 18 determines the presence or absence of a reception signal based on the input RSSI signal, and sends the determination result to the operation control circuit 19. The operation control circuit 19 controls the activation of the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 based on the determination result.

FIG. 2 shows a more preferred form of the receiving apparatus of the present embodiment.

In the embodiment shown in FIG.
Are composed of a comparator 20 for comparing the voltage level of the RSSI signal with a threshold voltage level (threshold), and a threshold voltage output circuit 21 for outputting a threshold voltage. The comparator 20 compares the voltage level of the RSSI signal with the threshold voltage level, and when the voltage level of the RSSI signal is higher than the threshold voltage level, determines that there is a received signal. If it is below the threshold voltage level, it is determined that there is no received signal. Also, the threshold voltage output circuit 21 here is
It is a circuit that continuously outputs a predetermined fixed level threshold voltage, for example, a constant voltage source.

Further, in the embodiment of FIG. 2, the second mixer 9,
Second local oscillator 11 and second local signal amplifier 1
In the case of 0, the operation is controlled by the bias current input from the bias current sources 25 to 27. The operation control circuit 19 further includes a second mixer 9 and a second local oscillator 1 based on the determination result of the received signal determination circuit 18.
The bias control circuit controls the supply of the bias current to the first and second local signal amplifiers 10. The operation control circuit 19 controls on / off of the bias current from each of the bias current sources 25 to 27 to the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 based on the output of the comparator 20. Switch 28
~ 30.

Next, the operation control of the second frequency conversion circuit 24 in the embodiment of FIG. 2 will be described.

First, the RSSI signal is output to the RSSI terminal 15.
Is input to the reception signal determination circuit 18 from the
The voltage level of the I signal and the threshold voltage level output from the threshold voltage output circuit 21 are compared by the comparator 20, and the presence or absence of the received signal is determined based on the comparison result.

When the voltage level of the RSSI signal exceeds the threshold voltage level, the comparator 20 determines that there is a received signal, and outputs a signal instructing the switches 28 to 30 to turn on the switches 28 to 30. 30. As a result, the switches 28 to 30 of the bias control circuit 19 are turned on, a bias current is sent to the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10, and the second mixer 9, the second local Oscillator 1
The first and second local signal amplifiers 10 are activated.

On the other hand, when the voltage level of the RSSI signal is equal to or lower than the threshold voltage level, the comparator 20 determines that there is no received signal, and outputs a signal instructing the switches 28 to 30 to turn off. To 30. As a result, the supply of the bias current to the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 is interrupted, and the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 Operation is stopped.

The second mixer 9 and the second local oscillator 11
And the on / off of the bias current input to each of the second local signal amplifier 10 and the second local signal amplifier 10 can be controlled independently of each other, so that the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 Controlling on / off of a bias current input to a part of the
Only a part of the operation of the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 may be stopped. However, in that case, the second
It is desirable to stop at least the oscillation operation of the second local oscillator 11 so as to prevent the second local oscillation frequency signal leaked from the local oscillator from interfering with other circuit parts.

For example, the switches 28 and 29 may be omitted from the operation control circuit 19 of FIG. 2 and the operation control circuit 19 may control only the bias current supplied from the bias current source 27 to the second local oscillator 11 by the switch 30. . In this configuration, the second mixer 9 and the second local signal amplifier 1
Although the power consumption is increased by the amount corresponding to the operation of “0”, the power consumption can be reduced as much as the power consumption of the second local oscillator 11 can be reduced as compared with the related art.

Here, the threshold voltage output circuit 21
The case where the level of the threshold voltage output from is constant has been described. However, the threshold voltage output circuit 2
The level of the threshold voltage output from 1 may be changed by a user operation.

That is, in the received signal determination circuit 18, the presence or absence of the received signal is determined by the comparator 20. For example, when the user knows that only the received signal of a certain level or more is received. In this case, when there is a received signal, the level of the RSSI signal should always be higher than a certain value. In such a case, the user may increase the threshold. This eliminates the need to activate the second frequency converter each time a weak signal other than the signal to be received is received. Therefore, the time in the standby state can be made longer, and the current consumption can be kept lower. That is, the user can change the determination level of the presence / absence of the received signal according to the usage environment.

The level of the threshold voltage output from the threshold voltage output circuit 21 is controlled by software control to R
The change may be made in accordance with the voltage level of the SSI signal.

Next, the threshold voltage output circuit 2 which enables the threshold voltage level to be variably set in accordance with the voltage level of the RSSI signal representing the received electric field strength by software control.
Example 1 will be described with reference to FIG.

In this example, the threshold voltage output circuit 21
A variable threshold voltage output circuit (threshold changing means) 31 for outputting a variable threshold voltage, and the above-mentioned threshold voltage level changing in accordance with the reception electric field level of the reception signal based on the input data signal. Variable threshold voltage output circuit 31
And a logic circuit (control means) 22 for controlling the operation.

A signal representing the voltage level of the RSSI signal, a code of a control program (software) for setting the threshold voltage level according to the voltage level of the RSSI signal, and the like are input to the logic circuit 22 as a data signal. It is supposed to be. By executing the control program, the logic circuit 22 sets the threshold voltage level according to the RSSI signal voltage level, and changes the threshold voltage level so that the threshold voltage level becomes the set value. A control signal for controlling the voltage output circuit 31 is output.

The variable threshold voltage output circuit 31 includes a constant voltage source 32, a plurality of fixed resistors 33 to 37 connected in series between the constant voltage source 32 and the ground, and switches 38A to 38A.
8D. Switches 38A-38
D is provided on the wiring connecting the points A to D between the fixed resistors 33 to 37 and the comparator 20. Only one of the switches 38A to 38D is turned on (connected) according to the control signal output from the logic circuit 22.
, Four different voltages (points A to D)
The potential of the comparator 2 as a threshold voltage.
0 is output. That is, switch 3
By turning on any one of 8A to 38D, the threshold voltage level is variable.

According to the above configuration, it is possible to set a more appropriate cutoff level (threshold) of the received signal according to the received electric field strength. Therefore, the presence or absence of a received signal can be determined more accurately.

As described above, the receiving device of the mobile radio communication device according to the present embodiment comprises the receiving signal determining circuit 18 for determining the presence or absence of a receiving signal based on the level of the output signal of the intermediate frequency amplifying circuit 8, Based on the determination result of the determination circuit 18,
When there is no received signal, the second mixer 9 and the second local oscillator 1
1 and an operation control circuit 19 for stopping the operation of the second local signal amplifier 10.

According to the above configuration, when there is no received signal, the operations of the second mixer 9, the second local oscillator 11, and the second local signal amplifier 10 are stopped. therefore,
It is possible to reduce unnecessary current consumption during standby. As a result, the power consumption of the receiving device can be reduced.

Further, according to the above configuration, the presence / absence of the received signal is determined based on the level of the output signal of the intermediate frequency amplifier circuit 8, so that the second mixer 9 and the The second local oscillator 11 and the second local signal amplifier 10 can be started.

Further, according to the above configuration, extra frequency components are removed by the band-pass filters 2.7, and the first
Converted to an intermediate frequency by a frequency conversion circuit, and
Based on the level of the received signal amplified by the high frequency amplifier circuit 3 and the intermediate frequency amplifier circuit 8, it is determined whether there is a received signal, that is, whether the apparatus is in a standby state. This makes it possible to accurately determine the presence or absence of a received signal while minimizing the influence of high-frequency noise.

Further, according to the above configuration, the oscillation operation of the second local oscillator 11 is stopped when there is no received signal, so that the second local oscillator 11 leaks from the second local oscillator 11 during standby.
It is possible to prevent the IF signal from interfering with other circuit parts.

The receiving device for a mobile radio communication device according to the present invention can be mounted on a mobile radio communication device such as a mobile phone, a notebook computer, or a portable information device and used. Further, the receiving device of the mobile radio communication device according to the present invention can be used as a receiving device of a mobile station in various mobile radio communication systems, but the short-range radio communication system “Bl
Bluetooth ”, which is the receiving device of the mobile station in“ e.
It is particularly suitable as an RF receiver IC for a Bluetooth interface.

In the receiving apparatus shown in FIG. 1, the circuit portion 41 or 42 surrounded by the dotted line shown in FIG.
It can be used as an RF receiver IC for the oot interface. That is, Bluetooth
h interface RF receiver IC, input terminal 1
May be provided, except for the input terminal 1 and the reception band-pass filter 2 may be provided.

It is to be noted that Bluetooth is 2.4G
This is a wireless communication system that uses the ISM (Industrial Scientific Medical) band of 1 Hz as a carrier frequency. In order to prevent interference with other wireless communication, using 79 frequency-hopping spread spectrum technology, 79 channels of 1 MHz width are used. The channel is switched at most 1600 times per second.

[0073]

According to the present invention, there is provided a receiving apparatus for a mobile radio communication apparatus.
As described above, the reception signal determination unit that determines the presence or absence of a reception signal based on the output signal of the intermediate frequency amplifier, and the second frequency conversion unit based on the determination result of the reception signal determination unit when there is no reception signal. Operation control means for stopping at least a part of the operation.

Thus, when there is no received signal, the second
At least a part of the operation of the frequency conversion unit is stopped, and wasteful current consumption during standby can be reduced. Therefore, the above configuration has an effect that a receiving device of a mobile wireless communication device with reduced current consumption can be provided.

Further, according to the above configuration, the presence or absence of the received signal is determined based on the level of the output signal of the intermediate frequency amplifier, so that the second signal is input when the received signal is input.
The frequency converter can be activated, and the influence of high-frequency noise can be suppressed, and the presence or absence of a received signal can be accurately determined.

Further, as described above, the receiving apparatus for a mobile radio communication apparatus according to the present invention comprises a receiving signal determining means for determining the presence or absence of a receiving signal based on the level of an output signal of an intermediate frequency amplifier; An operation control means for stopping at least one operation of the second mixer, the second local oscillator, and the second amplifier when there is no received signal based on the determination result of the means.

According to the above configuration, when there is no received signal, the operation of at least one of the second mixer, the second local oscillator, and the second amplifier is stopped. Therefore, it is possible to reduce unnecessary current consumption during standby. As a result, it is possible to reduce the power consumption of the receiving device and the current consumption of the entire mobile radio communication device.

Further, according to the above configuration, the presence / absence of the received signal is determined based on the level of the output signal of the intermediate frequency amplifier.
The mixer, the second local oscillator, and the second amplifier can be started, and the effect of suppressing the influence of high-frequency noise and accurately determining the presence or absence of a received signal can be obtained.

Preferably, the operation control means stops at least the operation of the second local oscillator when there is no received signal, based on the result of the judgment by the received signal judgment means.

As a result, an effect is obtained that the second local oscillation frequency signal leaked from the second local oscillator during standby can be prevented from interfering with other circuit parts.

In the above-described configuration for stopping the operation of at least the second local oscillator, the operations of the second mixer, the second local oscillator, and the second amplifier are controlled by an externally input bias current. And the operation control means cuts off the input of the bias current to the second mixer, the second local oscillator, and the second amplifier when there is no reception signal based on the determination result of the reception signal determination means. , The second mixer, the second local oscillator, and the second amplifier are preferably stopped.

Thus, when there is no received signal, the second
Since all operations of the mixer, the second local oscillator, and the second amplifier are stopped, the power consumption of all of the second mixer, the second local oscillator, and the second amplifier can be reduced. Therefore, the above configuration has an effect that power consumption can be further reduced.

In the receiving apparatus according to the present invention, the received signal determining means compares the level of the output signal of the intermediate frequency amplifier with a threshold value, and the level of the output signal of the intermediate frequency amplifier is higher than the threshold value. In this case, while it is determined that there is a received signal, it is preferable to determine that there is no received signal when the level of the output signal of the intermediate frequency amplifier is equal to or lower than the threshold value.

Thus, it can be determined that there is no received signal. Therefore, the above configuration has an effect that power consumption can be further reduced.

Further, the receiving apparatus having the above configuration controls the threshold value changing means for changing the threshold value and the threshold value changing means so that the threshold value changes in accordance with the level of the received signal. It is preferable to further include a control unit that performs the control.

As a result, it is possible to determine the presence or absence of a reception signal according to the reception situation. Therefore, the above configuration has an effect that the presence or absence of a received signal can be more accurately determined.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a receiving device of a mobile wireless communication device according to one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a part of the receiving apparatus and showing details of a received signal determination circuit and an operation control circuit.

FIG. 3 is a block diagram showing the reception signal determination circuit and showing details of a threshold voltage output circuit provided in the reception signal determination circuit.

FIG. 4 is a block diagram illustrating a configuration example of an RF receiver IC for Bluetooth.

FIG. 5 is a block diagram showing a configuration of a conventional receiving device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 input terminal 2 reception band bandpass filter 3 high frequency amplifier circuit 4 first mixer 5 first local signal amplifier 6 first local oscillator 7 intermediate frequency bandpass filter 8 intermediate frequency amplifier circuit (intermediate frequency amplifier) 9 second mixer 10th 2 local signal amplifier (second amplifier) 11 second local oscillator 13 demodulation circuit with detection circuit 14 output terminal 15 RSSI terminal 18 received signal determination circuit (received signal determination means) 19 operation control circuit (operation control means) 20 comparator 21 Threshold voltage output circuit 22 logic circuit (control means) 23 first frequency conversion circuit (first frequency conversion section) 24 second frequency conversion circuit (second frequency conversion section) 31 variable threshold voltage output circuit (threshold changing means) 41) Circuit part usable as RF receiver IC for Bluetooth 42 Bluetooth Circuit portion which can be used as a RF receiver IC for oth

Claims (6)

[Claims] A first frequency converter for converting a radio frequency signal into a first intermediate frequency signal; an intermediate frequency amplifier for amplifying the first intermediate frequency signal; and a first frequency converter for converting the first intermediate frequency signal into a first intermediate frequency signal. And a second frequency converter for converting the intermediate frequency signal into a second intermediate frequency signal having a frequency different from that of the intermediate frequency signal, the presence or absence of a received signal based on an output signal of the intermediate frequency amplifier. Signal operation means for stopping at least a part of the operation of the second frequency conversion unit when there is no reception signal, based on the judgment result of the reception signal judgment means. Receiving device of a mobile radio communication device. 2. A first mixer for mixing a radio frequency signal with a first local oscillation frequency signal to convert the mixed signal into a first intermediate frequency signal, and a first local oscillator for outputting the first local oscillation frequency signal An oscillator, a first amplifier for amplifying the first local oscillation frequency signal and supplying the amplified signal to the first mixer, an intermediate frequency amplifier for amplifying the first intermediate frequency signal, and an amplified first intermediate frequency signal A second mixer for mixing the second local oscillation frequency signal with a second local oscillation frequency signal to convert the second local oscillation frequency signal into a second intermediate frequency signal; a second local oscillator for outputting a second local oscillation frequency signal; A receiving device for a mobile radio communication device, comprising: a second amplifier for amplifying a frequency signal and supplying the amplified signal to a second mixer. Signal determination means; An operation control means for stopping at least one operation of the second mixer, the second local oscillator, and the second amplifier when there is no received signal based on a result of the determination by the received signal determining means. A receiving device for a wireless communication device. 3. The operation control means according to claim 2, wherein the operation control means stops at least the operation of the second local oscillator when there is no reception signal based on the result of the judgment by the reception signal judgment means. A receiving device for a mobile wireless communication device according to claim 1. 4. A second mixer, a second local oscillator, and a second mixer.
The operation of the amplifier is controlled by a bias current input from the outside, and the operation control means is configured to control the second mixer and the second local unit when there is no reception signal based on a result of the determination by the reception signal determination means. 4. The movement according to claim 3, wherein the operation of the second mixer, the second local oscillator, and the second amplifier is stopped by cutting off the input of the bias current to the oscillator and the second amplifier. A receiving device for a wireless communication device. 5. The received signal judging means compares the level of the output signal of the intermediate frequency amplifier with a threshold, and if the level of the output signal of the intermediate frequency amplifier is higher than the threshold, there is a received signal. And determining that there is no received signal when the level of the output signal of the intermediate frequency amplifier is equal to or lower than the threshold value.
The receiving device of a mobile wireless communication device according to any one of the above. 6. A threshold changing means for changing the threshold, and a control means for controlling the threshold changing so that the threshold changes in accordance with the level of the received signal. The receiving device for a mobile radio communication device according to claim 5, wherein: